Soybean oligopeptide with low allergenicity and little bitterness and preparation method and application thereof

Abstract

The present invention provides a soybean oligopeptide with low allergenicity and little bitterness and its preparation method and application. The preparation method includes the following steps: 1) mixing a soybean protein powder with water to obtain a soybean protein solution, and then performing thermal denaturation on the soybean protein solution, to prepare a denatured protein solution; 2) adjusting pH value of the denatured protein solution to 6-9, and then adding a neutral protease and papain to conduct a first enzymolysis, to obtain a first enzymatic hydrolysate; 3) adding an alkaline protease and a flavor protease into the first enzymatic hydrolysate to conduct a second enzymolysis, and after performing enzyme inactivation, to obtain a second enzymatic hydrolysate; and 4) centrifuging the second enzymatic hydrolysate, and performing membrane filtration on centrifuged supernatant liquid, to obtain the soybean oligopeptide with low allergenicity and little bitterness.

What is claimed is: 
     
         1 . A method for preparation of a soybean oligopeptide with low allergenicity and little bitterness, comprising the following steps:
 1) mixing a soybean protein powder with water to obtain a soybean protein solution, and performing thermal denaturation on the soybean protein solution to obtain a denatured protein solution;   2) adjusting pH value of the denatured protein solution to 6-9, and then adding a neutral protease and papain to conduct a first enzymolysis to obtain a first enzymatic hydrolysate;   3) adding an alkaline protease and a flavor protease into the first enzymatic hydrolysate to conduct a second enzymolysis, and after performing enzyme inactivation, to obtain a second enzymatic hydrolysate; and   4) centrifuging the second enzymatic hydrolysate, and performing membrane filtration on centrifuged supernatant liquid, to obtain the soybean oligopeptide with low allergenicity and little bitterness.   
     
     
         2 . The method in accordance with  claim 1 , wherein a mass to volume ratio of the soybean protein powder and water is 1: (5-10). 
     
     
         3 . The method in accordance with  claim 1 , wherein the performing thermal denaturation comprises: heating the soybean protein solution to 70-90° C., maintaining this temperature and continuously stirring for 20-60min. 
     
     
         4 . The method in accordance with  claim 1 , wherein an amount of the neutral protease is 10-100 U/g, an amount of the papain is 10-100 U/g, the first enzymolysis is conducted at 30-60° C., and time of the first enzymolysis is controlled to be 1-3 h. 
     
     
         5 . The method in accordance with  claim 1 , wherein an amount of the alkaline protease is 10-100 U/g, an amount of the flavor protease is 10-100U/g, and the second enzymolysis is conducted at 30-60° C., and time of the second enzymolysis is controlled to be 1-3 h. 
     
     
         6 . The method in accordance with  claim 1 , wherein the enzyme inactivation is performed at 110-120° C., and time of the enzyme inactivation is controlled to be 10-30 min. 
     
     
         7 . The method in accordance with  claim 1 , wherein the membrane filtration is performed using a filtration membrane with a pore diameter of 1-200 nm. 
     
     
         8 . A soybean oligopeptide with low allergenicity and little bitterness prepared by the method according to  claim 1 , wherein in the soybean oligopeptide with low allergenicity and little bitterness, content of glycinin is less than 200 mg/kg, content of β-conglycinin is less than 150 mg/kg, and content of soybean trypsin inhibitor is less than 100 mg/kg. 
     
     
         9 . The soybean oligopeptide with low allergenicity and little bitterness in accordance with  claim 8 , wherein content of peptides with a molecular weight of less than 5000 Da in the soybean oligopeptide with low allergenicity and little bitterness is greater than 85% by weight, and content of peptides with a molecular weight of less than 1000 Da is greater than 60% by weight. 
     
     
         10 . Use of the soybean oligopeptide with low allergenicity and little bitterness in accordance with  claim 8  in milk powder or health food.